74LS170-4×4 Register File


The 74LS series of integrated circuits (ICs) was one of the most popular logic families of transistor-transistor logic (TTL) logic chips. 74LS series is a bipolar, low-power Schottky IC. The 74LS170 contains 16 high-speed, low-power, transparent D-type latches arranged as four words of four bits each, to function as a 4×4 register file.

74LS170 Features

  • Simeltaneous Read/Write Operation
  • Expandable TO 512 Words Of n-Bits
  • Typical Acess Time Of 20 ns

74LS170 Specifications

Supply Voltage4.75 – 5.25Vdc
Maximum Clock Frequency40Mhz
Power Dissipation2mW/gate @100kHz
Minimum Output Current8mA
Propagation Delay10nS
Fan Out (TTL Loads)20

74LS170 Pinout Diagram

74LS170 Pin Description

Pin NoPin NameDescription
1D2Data Input
2D3Data Input
3D4Data Input
4RBRead Address Input
5RARead Address Input
6Q4Data Output
7Q3Data Output
9Q2Data Output
10Q1Data Output
11RE’Read Enable Input (Active Low)
12WE’Write Enable Input (Active Low)
13WBWrite Address Input
14WAWrite Address Input
15D1Data Input
16VCCPositive Supply


  • Storing data in digital form

Download 74LS170-4×4 Register File Datasheet from the link given below.